Network congestion or timeouts can cause disconnections and since they can happen at any point in the network path they are pretty difficult to identify. SmartFoxServer cannot detect which failure happened to an external hop in the network path.

And this is not unique to SmartFoxServer, any application is unable to do that. You would need a complex network analysis to find out the precise reason for a disconnection that is not cause directly by one of the two endpoints.

Lapo wrote:Network congestion or timeouts can cause disconnections and since they can happen at any point in the network path they are pretty difficult to identify. SmartFoxServer cannot detect which failure happened to an external hop in the network path.

And this is not unique to SmartFoxServer, any application is unable to do that. You would need a complex network analysis to find out the precise reason for a disconnection that is not cause directly by one of the two endpoints.

When I got reason = unknown. Server print error log like below. what was the error mean?

This is a different error, not sure if related, could be.It simply means that the client that has sent an Extension request does not exist as User in the system. In other words the client is not logged in.

It could be that the error is generated after the client has disconnected. If this is the case it simply indicates that some Extension requests where still in the queue waiting to be processed while the client got disconnected. When the system finally processes these requests it rejects them because the client is no longer connected.